Spark plug



April 5, 1927.

v E. B. NOWOSIELSKI S PARK PLUG Filed Jan. 2. 1925 Patented Apr. 5, I

UNITED- STATES .1',6z3,129 PATENT OFFICE.

" EDWARD B. NOWO S IELSKI, OF BLOOMFIELD, NEW iIERSEY, ASSIGNOR TO SPLITDORI ELECTRICAL COMPANY, OF NEWARK, NEW JERSEY.

1 SPARK PLUG.

application filed January 2, 1925. Serial No. 270.

- This invention. relates to improvements in spark plugs, and has for its principal object, the construction of a' plug, particularly, of the mica type in which the mica washers, constituting the insulators, are so locked in position that they cannot get loose and out of place from the various changes in temperature conditions, or from varying pressures within an engine cylinder either with, or without the presence of oil or moisture;

Another object of my invention is to provide means for carrying away the heat and thus to prevent warping of the central electrode parts whereby a more stable and better plug is secured.

It is well known that in high powered and heavy duty engines the strains that are placed on the spark plugs is enormous with a consequent result that the insulators, be-

come cracked or misplaced and soon are disabled. From tests which have been made on the plug herein disclosed, I believe I have overcome many'of the former difficulties encountered. f f

My invention will best be understood by reference to the drawing which illustrates substantially a full sized section through the plug showing the shell 1 adaptably screwed 1n the engine cylinder by means of the threads 2. The shell has a tapered bore 3, at the small end of which is arranged one or more ground electrodes 4; the other end of the shell. A counter-bore, somewhat larger in diameter than the largest portion of the bore 3 is rovided, and in this counter-bore is carrie the central electrode unitary structure comprising a metallic member 5, having a collar 6, preferably integralthere- .with; the surface of the collar 6, away from the sparking end 7, is dished at 8, around the electrode 5. Wrapped around the electrode 5, is a layer of mica 9, and, positioned over the wrapping 9, are insulators 10 and 1* each made up of a stack of mica washers. Between the two stacks 10 and 11 is'positioned a relatively heavy collar 12, preferably of good heat conducting material, such as copper or aluminum.

As will be seen in the drawing, the collar 12 is fitted over the mica' wrapping 9, be-

.tween the insulators 10 and 11. The collar manner as the collar 6.

12 is dish shaped on both sidesin a similar It is to, be understood that this dishing may be readily accomplished by striking the collar 12 in a proper die. The outer end of the electrode is threaded at 13, and a clamping nut 14, and washer 15, are provided for drawing the insulators 10 and 11 together with the collar 12, against the collar 6 of the electrode. The terminal nut 16 is used for making connections to the spark plug. From the construction of the collars 6 and 12 will be seen that the mica washers are forced into the dished portions and are there locked in position so that thiechanges, due to variations of temperature, taken in connection with the pressure applied to the plug from within the engine cylinder, cannot possibly loosen the mica washers and displace them. After the assembly of the unitary central electrode construction has been completed, the insulators 10 and 11 are turned down, the insulator 11 being preferably made tapered in form to leave a space 3 between it and the shell 2. A means for holding the central electrode structure between the shell 1 is provided by the flange 17 which is preferably spun over the collar 12 after same has been set into the counter-bore provided. Since the metal 12 is preferably somewhat soft in structure, the holding means 17 on the shell imbeds itself more or less into the collar 12 thereby securely sealing the chamber of the shell. It will be seen that the collar 12, in addition to the functions already described for it, acts as a gasket and due to its large area contact with the shell 1, acts to convey the heat away from "the central electrode 5 to the outer portion of the shell, It will be further observed that electrode 5 is much heavier than the central electrodes heretofore used, the idea of this is to provide an electrode which will carry away the heat without warping. Y j i i It will be apparent to one skilled in this art that various changes in the details may of my invention or the scope of the appended claims.

Having thus described my invention 'what I claim is:

be made without departing from the spir1t 1. In a spark plug, a shell having a cenend an insulator around the electrode and extending from the collar to a point closely adjacent said threads, an insulator positioned over said first insulator and having one end engaging said collar, a relatively heavy collar of good heat conducting material dished on both sides and positioned over the first insulator and against one end of the second insulator, a third insulator positioned against the other side of said heavy collar, means on the threads for clamping the last two mentioned insulators and heavy collar in position with respect to the first collar; said heavy collar being positioned in said counter-bore and a turned over portion of the shell for gripping said heavy collar as and for the purpose described.

2. In a spark plug, a shell having a central tapered bore and a counter bore at one 'end larger in diameter than the greatest diameter of the central bore, a unitary central electrode assembly comprising; a metallic electrode having a collar near the sparking end and clamp engaging means on the other end, said collar being dished on its side away from the sparking end, an insulator around the electrode and extending from the collar to a point closely adjacent said clamping means, an insulator positioned over said first insulator and'having one end engaging said collar, a relatively heavy collar preferably of soft metal dished on both sides and positioned over the first insulator and against one end of the second insulator, a third insulator positioned against the other side of said heavy collar, means cooperating with said clamp engaging means for securing the last two mentioned insulators and heavy collar in position with respect to the first collar; said heavy collar being positioned in said counter-bore and it turned over portion of the shellfor gripping said heavy collar as and for the purpose described.

3. In combination with a spark plug shell having a central bore, a counter-bore and a central electrode holding means comprising the edge of said counter-bore, which edge is adapted to be turned inwardly to form holding means; a unitary central electrode structure comprising; a metallic electrode having a collar toward the sparking end, said collar being dished on its side away from the sparking end, an insulator extending from said collar longitudinally toward the other end of the electrode, an insulator positioned over the first mentioned insulator. and seated on the dished collar, a third insulator, a relatively heavy collar dished on both sides positioned over the first insulator and between the second and third and clamping means onthe electrode for holding the last two insulators and the heavy collar in position with res ect to the collar on the electrode; said hol ing means on the shell gripping said heavy collar to hold it and the unitary structure securely in the shell.

4. In combination with a spark plug shell having a central bore. a counter-bore and a central electrode holding means comprising the edge of said counter-bore. which edge is adapted to be turned inwardly to form holding means: a unitary central electrode struc lure comprising: a metallic electrode having a collar toward the sparking end, said collar being dished on its side away from the sparking end. a wrapping of mica extending from said collar longitudinally toward the other end of the electrode, a stack of mica washers around the micawrapping and rest iug against the dished collar, a double dished mounting collar fitting over the mica wrapping and resting on said stack of mica washers, a second stack of mica washers around the mica wrapping and seated on said double dished collar and means on the electrode for clamping the mica washers against the mounting collar and the electrode collar; said holding means on the shell being adapted to grip said mounting collar to hold it and the unitary structure securely in the shell.

5. In combination with a spark plug shell having a central tapered opening, a counterbore at the larger end of the taper and greater in diameter than the greatest diam eter of the central bore, said counterbore terminating in a holdingflange, a unitary central electrode structure having a relatively heavy metal collar seated in said eounterbore and adapted to have said flange spun over said collar to hold the unitary structure in place, a pair of insulators, said collar being dished on both sides to form securing means for said insulator located one on each side thereof, a central electrode and a separate longitudinal insulator therefor; a dished collar near the sparking end of the central electrode to form securing means for one side of said pair of insulators and means on the outer end of the central electrode for drawing and holding securely together said unitary electrode structure.

6. In a spark plug, a shell, a unitary central electrode structure comprising; a heavy metal electrode having a dished collar near the sparking end, a heavy relatively soft dished metal collar positioned over but insulated from the metal electrode and intermediate its ends, a pair of insulators seated one on each side of the heavy dished collar, means on the metal electrode for drawing the pair of insulators and the heavy collar against the collar on the electrode and means for engaging the heavy collar to hold the same securely in the shell.

7. In a spark plug having ashell, means for increasing the effectiveness of the plug structure, comprising; a heavy central electrode, a relatively heavy cop er collar positioned intermediate the ends of the electrode but insulated from 'the electrode, a collar near the sparking end of the electrode,

a pair of insulators consisting of stacks of mica washers, said collars being formed so as to secure the mica washers when compressed, especlally from lateral movement, 

